A striking and characteristic feature of very young children with ASD is their reduced interest in people in their immediate environment: they frequently focus more on the toys and objects in the room and less on adults who are in close proximity. While the phenomenon of apparent heightened interest in objects in toddlers with ASD is not well understood, it has been documented as early as the first birthday. These early differences in attention in toddlers with ASD may be part of a developmental cascade that leads to a more intense focus on objects at the expense of attending to people. Such a preference for objects over people can interfere with opportunities for social learning and may also contribute to difficulties in the acquisition of language and problem solving skills. Indeed, a fundamental goal of behavioral therapy for children with ASD is to shift their attention away from objects and towards parents, teachers, and peers. The main goal of the current proposal is to elucidate the perceptual processes that serve to bias toddlers with ASD toward objects and drive their unusual exploratory behaviors. We will focus on two perceptual dimensions that in our previous work have been found particularly important in driving attention of toddlers with ASD: contrast and motion. We are taking a novel two-pronged approach, incorporating eye-tracking tasks with analogous behavioral tasks to examine the associations between visual preferences as exhibited in a context of eye-tracking experiments and attentional biases (preferences) observable during free play situations. The proposed study will address the following questions: (1) Are toddlers with ASD biased toward high-contrast stimuli? (2) Are certain kinds of motion such as rotational movement especially salient to toddlers with ASD? (3) Does the presence of perceptually salient distractors impede attention to social stimuli in toddlers with ASD? We plan to conduct these experiments with 18-24-month-old toddlers who are exhibiting signs of ASD. Targeting this group is critical from a clinical standpoint, as abnormalities in visual attention (e.g., unusual visual interests) constitute part of the diagnostic criteria for ASD, yet these difficulties often manifest at this age only in a limited form. Thus, designing more sensitive behavioral approaches to detect emerging abnormalities in this domain is vital. Through these experiments, we will elucidate the perceptual components of stimuli that attract toddlers'visual attention and effectively draw them away from social experiences that are critical to their development. PUBLIC HEALTH RELEVANCE: The proposed experiments focus on visuo-perceptual abnormalities in the early stages of ASD, perhaps even prior to the manifestation of behavioral symptoms in this area, and thus advance our understanding of the processes and mechanisms underlying behavioral symptoms of the disorder. By shedding light on the mechanisms that lead to deficits in attention to social stimuli in everyday situations in young children with ASD, the project's findings will inform interventions that aim to minimize the cascading effects of such deficits over the first years of life. Furthermore, our findings could be highly consequential for the design of early diagnostic measures for high-risk infant sibling populations or infants with emerging but unclear symptoms of ASD.